1. Field of Invention
The present invention relates to a stator structure and a micromotor having the same, and more particularly to a micromotor and a manufacturing method therefor, wherein the stator structure is constituted by a flexible printed circuit (FPC) configured with the required electrical elements of the micromotor.
2. Related Art
In a conventional micromotor, a stator includes primarily a magnetoconductive housing which is provided with upper and lower pole plates and is formed by stamping, bending and welding a magnetoconductive material in sheet form; and coil windings which are configured on the magnetoconductive housing. However, in stamping, bending and winding processes, due to lots of upper and lower pole plates and great length for winding, the processing of stamping, bending and winding may have considerable difficulty in manufacturing. In addition, it is difficult to further reduce a size of the micromotor. As a result, manufacturers try to apply flexible circuits to the stator.
For example, the U.S. Pat. No. 4,665,331 discloses a brushless DC (Direct Current) micromotor, wherein the stator coil is formed by coaxially winding more than one coil winding formed on an insulating sheet, on which coil winding a plurality of coil patterns are continuously provided in series in the direction of winding, and a control unit of the motor supplies electricity to provide magnetic thrust force of different phases, such that a rotor in a center of the motor can be pushed (or driven) to rotate.
Yet, the prior art only considers how to configure the coil windings, whereas other electrical elements or the control unit will be still configured in a motor case by other assembling means. Therefore, it is unable to effectively reduce an assembling time and flow of the motor. In addition, to allow the brushless DC micromotor to rotate successfully, the Hall devices or similar elements is adopted to be deployed to sense magnetic poles of the rotor, thereby sensing a position of the rotor to transmit the position information of the rotor to the control unit of the micromotor. The control unit will then control an operation of the coil windings, depending on the position of the rotor, to switch among phases. Besides, to enable the motor to be applied to a high precision control field, it may need to install a more precise position encoder. Nevertheless, the installation of the position encoder or the Hall devices will add more steps in the assembling procedure of the micromotor and will in turn spend more manufacturing man-hours and cost. Furthermore, as each element is not aligned easily, it will further affect yields of the micromotor.
Accordingly, it is an issue to be thought of by existing manufacturers to effectively provide a micromotor for which manufacturing processes can be decreased, a cost can be reduced, an accuracy of sensitive of a rotation position of the motor can be improved, and an entire size can be maintained or miniaturized.